On 11 May 1998, India joined the nuclear club when it simultaneously conducted three nuclear tests at Pokharan in the Rajasthan desert. Code named Operation Shakti-1, they were part of a series of five tests held as a joint project of India's Department of Atomic Energy (DAE) and the Defence Research and Development Organisation (DRDO).

According to the Indian government, the five tests involved: a 12 kiloton (kT) fission device, a 43 kT "thermonuclear [fusion] device," a low-yield device, and two sub-kiloton devices. Although U.S. intelligence analysts speculated that the largest test was of a boosted nuclear weapon, the head of India's Atomic Energy Commission, Dr. Rajagopal Chidambaram, insisted that New Delhi had tested a thermonuclear bomb. He noted that the yield was deliberately kept low to minimize damage to the surrounding area but that India has the ability to make much larger hydrogen bombs.

That New Delhi can indigenously design and produce the full range of nuclear weapons, from tactical bombs for battlefield use to city-busting thermonuclear warheads, should come as no surprise to the international community. India tested its first nuclear device in 1974 and has developed an enormous nuclear infrastructure since. While India may have relied on foreign technology in the early stages of its weapons program, it now has an "in-house" capability to design and produce all the components necessary for making nuclear weapons and the ballistic missiles which can carry them.

The devices used in the recent tests were designed and developed by personnel from the Bhabha Atomic Research Centre (BARC), where most of the work was carried out. Located near Bombay, BARC is the nerve-center of India's nuclear weapons program. The Saha Institute of Nuclear Physics in Calcutta assisted in the design effort, providing expertise on fusion (thermonuclear) technology and tritium production. The weapons were designed using powerful supercomputers, which India is capable of producing indigenously at the Centre for Development of Advanced Computing in Pune.

The plutonium for the five tests was produced at BARC's 100 megawatt Dhruva research reactor, which began operations in 1985. Dhruva provides the majority of the plutonium-bearing spent fuel for New Delhi's nuclear weapons program, producing up to 16-26 kilograms of weapons-grade plutonium every year. The spent fuel is sent to reprocessing plants at BARC and the Indira Gandhi Centre for Atomic Research in Kalpakkam to separate out the plutonium. BARC personnel have also developed uranium enrichment technology using ultracentrifuges, and have built two enrichment facilities: an experimental-scale laboratory at BARC that can produce 2 kg of weapons-grade uranium per year and a larger plant at Rattehalli that can produce 28 kg per year. India has stockpiled enough fissile material to build 80-100 nuclear weapons and has the capability to produce much more.

Once the fissile material [plutonium or highly enriched uranium] is extracted, it is converted into metallic form at BARC. BARC has also developed the capability to produce the non-nuclear special materials needed to build advanced atomic bombs, including tritium and beryllium. The Nuclear Fuel Complex in Hyderabad has assisted in this effort and can provide some materials and specialized equipment, while the Centre for Advanced Studies in Indore has developed nuclear triggers.

DRDO facilities including the Defence Metallurgical Research Laboratory and the Defence Research and Development Laboratory in Hyderabad helped fabricate the devices and weaponize them. DRDO personnel provided systems engineering, in addition to producing the detonators, high-volt triggers, and safety locks for command and control. Other DRDO labs provided technology and expertise on aerodynamics, arming, and fusing.